Safety device and indicator for steam-boilers.



G. E. WHITNEY. SAFETY DEVICE AND INDICATOR POR STEAM BOILEBS.

APPLICATION FILED DEO. 11, 1899.

Patented Dec. 22, 1908.

` UNITED STATES PATENT OEEICE GEORGE E. WHITNEY, or BOSTON, MASSACHUSETTS, AssIGNOR, BY 'MESNE ASSIGNMENTS, To STANLEY MOTOR CARRIAGE COMPANY, A CORPORATION or MASSACHUSETTS.

Specification of Letters Patent.

Patented Dec. 22, 1908*.

Application led December 11, 1899. Serial No. 739,911:

vention being particularly useful in connection with boilers that are used in motor vehicles and the like where frequently inexperienced persons are required to look after the boiler and keep it properly filled with water.

The aim bf'my invention -is to provide a safety device, lirst that will indicate when the water level has dropped below the safety linesecond, to combine such a device in a novel manner with the" heating means employedior heating they water in the boiler, and third, to improve a device of this class in various other particulars, all as will be here# inafter described.

- In the drawings, Figure 1 in elevation, partial section, shows a boiler equipped witha device in accordance with my invention, and Figs. 2 andA 3, enlarged sectional details to be referred to.

Referring t`o the drawings, in the embodiment of my invention selected for illustration therein, A is an u right boiler of usual type, havingv tubes a lieneath'which is arranged a combustion chamber B containing suitable heating means, as the burner b, but so far as my invention is concerned the boiler may be otherwise constructed and heated byv other suitable means if desired.

In carrying out my invention as herein disclosed, one of the tubes, for instance, a tube closely adjacent the barrel of the boiler, is severed, see Fig. 2, and a T-shaped fitting or seat c is brazed, welded or otherwise secured in position j oinin the ends oi the separated arts Oi the sai tube, said seat or fitting raving a laterally extended neck-portion c. This neck c is interiorly threaded to receive the exterior threaded surface of the conical plug d, shown as closed'at its`.inner end dx where exposed to` the intense heat ofV the products of .combustion risin within the tube a. This plug d has drille or otherwise formed within ita passage d', leading inwardly from the outer end ofthe plug and terminating adjacent the end dx'o the plug in a wedgeshaped or tapering chamber, which is run ful-l of solder or material e, constituting one form of fusible plug, and the said fusible material or plug may be otherwise inserted if desired, it being held in place, as herein shown, by the shoulder d2, surrounding the passage d' near the end of the fusible plug e. Lateral openings d3 in the plug d are normally in register with perforations c2 in the neck c of the litting c.

At a point in the Shell or barrel of the boiler, axially in line with the axis of the plug d, is an interiorly threaded o ening, Into which is screwed the tube f, interiorly threaded at its inner end, so as to be screwed u on the exteriorly threaded end of the neck c as shown best in Fig. 2. The outer end of this tube f is closed by a threaded cap f or in any other suitable or desired manner, so long as the closure is rovided with means', as' the lug f2, by whic they closure may be readily unscrewed or removed to expose the chamber formed within thev tube f. A branch pipe g leading outwardly preferably near the top of the `chamber within the tube f is iitted with a T itting g', with one side oi which is connected the whistle g2, constituting one form of audible alarm, andwith the o posite side of which is connected a pipe g3 tliat leads to the feed pipe t of the burner b, Fig. 1. A valve g4 in the pipe g', and a valve g5 in the pipe g3 provide means'for positively controling these pipes, as necessary.

The operation of the device thus far described is as follows: Assuming the boiler to be i-n normal operation, the water level is considerably above the fusible plug, as clearly indicated in Fig. l, and when the plug andthe fitting c, within which it is arranged, are buried in the water, as in Fig. 1, the water rotection is such as to prevent fusing Ol the lusible plug e by the action of the heat of the products of combustion within 'the tube a.' When, however, the Water level by accident or Otherwise falls below the level of the plug, the latter will be deprived of the protection theretofore furnished by the water and will ,fuse or melt under the excess or excessive temperature to which it is now subjected by the products of combustion within the tube, and will flow out through thei passage d into lthe chamber within the pipe thereby establishing a connection between apertures c2, d3.

the steam space of the boiler through the openings c2, d3, and the passage d into the said chamber, from whence the steam immediately passes through the pipe g to the whistle g2, sounding an alarm thereat, and at the same time flows dovm through thepipe g3 into the feed-pipe b of the burner, thereby interrupting the continuous flow ofthe liquid fuel therethrough to the burner, and eX- tinguishing the flame at the latter. A check valve bf in the feed pipe prevents the steam pressure reaching t-he supply tank fromdvhich the fuel supply is taken. rl'hus while the boiler is in use, if by lack of attention the Water level is perniitted to drop to or below the danger point, the fusing of the plug sounds an alarm, thereby indicating that the level is dangerously low, and at the same time extingulshes the flame that would otherwise continuato enerate steam and drop the Water level stil lower.

Obviouslv, either the audiblealarm or the cuttin f off bf the fuel to the burner, may be used a one and vwithout the other, the cutting off of the fuel as described constituting oneA means ofcontrolling the heating means for the boiler. rl'he plug having blovm in this'manner, the valves g4 and' g5 may beclosed, cutting off further escape of the steam, andthe boiler filled and continued in use without replacing the fusible plug, since the steam escaping into the chamber f cannot escape into the boilertube a and thence into the fire-box, because of the closed end ofthe outer plug d, the plug in this respectdiffel-ing from any plug for insertion in boiler tubes heretofore knoun to me. By removing the closure f access may be had to the chamber f to periritremoval of the plug d and insertion of a new plug or to pernit the refilling ,of the vplug d with fusible material, so that the plug is in effect arranged Within an accessible chamber that is accessible from the outside of the boiler to pcrrr it of convenient 'replacing of the plug, which would not be possible were the accessible chamber omitted.. In case the steam v'ithin the boiler has not entirely escaped, and to prevent it escaping vithin the chamber and outwardly therefrom during the insertion lof a neu` plug,vsuitable means 1r ay' be 'provided for closing temporarily ene or the other of the One form of means forthis purpose is shoi n in the drav'ings, Figs. 1 and 3, the same consisting of a ring h encircling able n anner, as by a rod h2, rising through a suitable stuffing box in the upper tube sheet of the boiler, as shown in Fig. 1. 'Ihus when it' is desired to replace the plug While steam is still in the boiler, the rod h2 may be de-V pressed, thereby closing the apertures c2,- the closure f nay then be removed and the plug replaced Without any difficulty from escaping steam. After the new plug has been inserted, the rin h is again rotated by raising the rod h2 to c ose the apertures c2 and leave the plu in condition for again indicating the danger 'evel of the vfater.

Referring ,to Fig. 2, it Will be noticed that the outer plug d is grooved exteriorly and circumferentially at the point Where the apertures d3 are located, so that in case the operator in inserting a new plug does not turn the same so as tobring the apertures d3 into exact register With the apertures c2, steam entering through the latter may'still reach the apertures in the plug by traveling around through the groovedt. Thus it is possible to turn the plug into one or another of its different rotative ositions and still have it perfectly operative. In the drawing the plug is shown 1n position vv ith its apertures d standingy vertically, that is, in a vertical plane, the plug being so shown for the sake of clearness, but in practice I prefer to turn the plug into position with its, a ertures in a horizontal plane one with the ot er, and also I prefer that the apertures in the neck c of the tube fitting, be also arranged horizontally instead of vertically, or at least to eliminate the aperture or apertures that lie below the horizontal diameter of the plug, so as to prevent the fused metal of the plug e from escaping through such apertures and forming a deposit atV the bottom of the boiler. I

While I have herein described my invention in one embodiment thereof, .vet my said invention is notv restricted to this embodiment alone, for obviously it may be varied v within the spirit and scope of the invention here disclosed and set forth in the claims.

As far as I know I am the first to provide a fusible plug that is inserted in a boiler tube, as in this case, yetis inclosed Within an outer shell or tube, that permits the plug to receive the full benefit of the heat within the tube, vet prevents'V anyr escape of liberated steam into the tube or the products of combustion out from the tube. I am also the first, so ,far as I am aware,'to provide a fusible plug in connection with a boiler tube and arrange said plug in an accessible chamber, that is, a chamber accessi-ble from the outsidel of the boiler, without opening up the steam space. I am also the first so far as I am aware toprovide in connection with a safety device of the character describedI that is responsive to changes in heat and is normalllsv protected by water within the boiler, an vaudible valarm and heat controlling means, or either' of them.

Having described one embodiment of my invention and without limiting myself as to detail what I claim and desire to secure by .Letters Patent, is l l y 1. Aboiler having a crown sheet and re tubes secured therein, one of said fire tubes l being provided with an excess temperature `indicating device, restrained from operation by the protective action of the water in said boiler, and normally accessiblefrom theexterior of the boiler. p Y

2. A boiler having a crown sheet and fire tubes Asecured therein, one of said fire tubes being provided at a point above lthe crown sheet with an excess temperature device normally restrained from operation by the proe tective action of the water in said boiler; and an alarm device connected with and operatedy by the action of said excess temperature de-` vice.

3. A verticaltubular boiler having a plurality of fire tubes. one of'which is provided with a safety fluid escape devicevresponsive to the changes in temperature and arranged below the normal water level in the' boiler, 25 and an externally accessible chamber for said device at the side of said boiler.

4. A vertical tubular boiler having-a plurality of lire tubes one of which is fitted with a fiisible plug, and an externally accessible chamber furnishing -access to said fusible plug at the side of said boiler.

5. A vertical tubular boiler one of the fire tubes whereof isfitted with a fusible lug, an externally accessible chamber furnisliing access to said fusible plug, at theside of said boiler andan external closure for said chamber.

(LY-A vertical boiler one of thefire tubes of which is provided with an internally arranged excess heat indicating device, and a closed externally accessible chamber furnishing access to said device at the side of said boiler.

7. A tubular boiler -having iire tubes, a cup shaped, exteriorly threaded member screwed into one of the fire tubes and having its inner end closed, said'member containing one or more -perforations external to the tube, and a mass of fusible material within said member and normally closing the perforation or perforations therein.

8. 'I he combination with a tubular steam boiler of a fusible plug arranged in connection with one of thetubcs of said boiler, a chamber into which steam is discharged by the fusing of said plug, a liquid fuel burner to supply heat to said boiler, and a connection between said chamber and the feed for said burner, to operate as described.

9. 'Ihe lcombination with a tubular steam boiler, of a fusible plug arranged in connection with one of the tubes of said boiler, a l chamber' into which steam is discharged upon fusing of said plug, aI liquid fuel burner to i supply heat to said boiler, a whistle, and conl t nections between said chamber and said l .said plug.

plug.

whistle and the feed for said burner, to oper- -ate substantially as described.

tion with one of the tubes of said boiler, a

i chamber -into which steamis discharged uponfusing of said plug, a liquid fuel burner tov supply heat to said boiler, fawhistle, and con- -nections between said chamber and said whistle and thefeed for said burner, and

8 0 chamber into which steam is discharged upon fusing of said plu ,"a liquid fuel burner to supply heat to sai boiler, a whistle, connections between said chamber and said whistle and the feed for said burner, and a heck valve also in said burner feed' but at the opposite side of said connection from said burner.

- 12. The combination with ay steam boiler, of a fusible 'lug arranged therein s o as to be acted upon by the heat from the products of combustion and normally cooled by the protective action of the Water in said boiler, said plug containing one or more openings through which steam is discharged upon fusing of said plug, means providing access to said plug for renewal of the same, and means to stop escape of steam through said opening or openings while the plug is being replaced.

13. The'combination with a tubular steam boiler, of a lateral tubular and perforated extension upon one of the tubes thereof, a fusible plu arranged in said extension, and

`normally c osing the perforation or perforations thereof, and means to close said perforation or perforations tol permit renewal of 14. The combination with a tubulargsteam boiler, of a lateral tubular and perforated vextension upon one of the tubes thereof, a

fusible plu arranged in said extension and .normally c osing the perforation or perforations thereof, .and means accessible from the exterior of the boiler to close said perforation or perforationsto permit renewal of said 15. The combination with a tubular steam boiler, of a lateral tubular and perforated extension upon one of the tubes thereof, a fusible 1 20 plug arranged in said extension and normally closing the perforation or perforations thereof, and a closing device surrounding said lateral perforated extension and operable from the exterior of theboiler to close said perforations, to permit renewal of said plug.

16. ,The combination with a tubular steam boiler, of a fusible plug connected with one of the iire tubesof said boiler and subject to the heat of the products of combustion passing therethrough, means to heat said boiler within said plug and an exterior connection and connections between said fusible plug normally closing the perforations in said exand heating means for rendering the latter tension but adapted to uncover such perrinoperative for heating upon blowing of said forations in diterent rotative positions.

5 plug. p In testimony whereof, I have signed my 17. The combination with a tubular steam name to this 'specilicatiom in the presence of boiler of a lateral tubular and perforated eX- two subscribing witnesses.

' tension upon one of the tubes thereof, a GEORGE E. WHITNEY.

fusible plu .arran ed in said extension and Witnesses:

10 normally c osing t e perforatoin or perfora- FREDERICK L. EMERY,

tions thereof by means of the fusible material LAURA T. MANIX. 

